在MySQL数据库中选择php-session-id作为主键是一个好主意吗？

Question

Is it a good idea to choose php-session-id as primary key in a MySQL-Database? Will there be unexpected surprises?

Why I am asking this question: I want to store visitor-behavior and want to identify visitors on their session-id at that time.

I do not know exactly what criteria a PHP session ID is generated. That's why I also do not know if someday might exist duplicates.

EDIT2: Aside from performance issues a session ID is not always unique. Therefore, one should not use it as a PK. See here Link1

Answer 1

This is not a good idea because, primary keys are advised to be integers which helps for indexing. If session ID is unique of course you can use it as a database primary key but i hope you consider not to for the sake of your database design and speed.

Why I am asking this question: I want to store visitor-behavior and want to identify visitors on their session-id at that time.

Why don't you add non primary key column called session-id ? You can still identify them that way.

About uniqueness, please refer to this link